Round 15 Results

My ELO model has completed a clean sweep of 4 out 6 tips for the bye rounds on the weekend, incorrectly tipping against Gold Coast and the Western Bulldogs. It was far and away the best round of the year for margin tipping, with an MAE of 16.5! That gives us a season total of 92 tips from 120 games (73%) and an MAE that has tipped under 30, sitting at 29.4.

With such a tight MAE, there isn’t a lot of movement in our ratings this week since each team performed relatively close to where our model expected. The obvious big movers are Gold Coast and St Kilda, after the big win by the relatively weaker rated Suns. Adelaide remains relatively clear on top of the ratings after the 2nd, 3rd and 4th teams all had byes.


The biggest impact on our finals simulations last week, as measured by the match importance rating was certainly the Sydney v Bulldogs game, is would be expected by a matchup between two top 4 sides. The last minute goal to Jason Johannisen saw the Bulldogs leapfrog the Swans on our simulated season ladder. The Swans top 4 aspirations took a hit, dropping from 54% down to 44%, while the Bulldogs top 4 chances jumped from 34% to 46%. Given the tightness on the actual AFL ladder this season, there should be a few more of these big impact games coming up!


The race for the top 2 didn’t change too much after the weekends matches, again, likely due the bye for 3 of our top 4 sides. The Crows and Hawks remain almost 50% chances get finish inside the top 2.

Port has improved its chances of dislodging one of the top 8 after its win on the weekend, jumping up to a 28% chance. The most likely of our top 8 to drop out is North Melbourne, who miss the 8 in 18% of simulations, despite their fantastic start to the season.




Round 14 Results

Continuing through the bye rounds, this week saw my ELO model managed to another 4 of the 6 games tipped correctly, with an MAE of 24.8. The two games we got wrong were the Friday night clash between Collingwood and Freo (we gave Freo a slight edge at 53%), and the enthralling upset win of St Kilda over Geelong.

We didn’t see a whole lot of movement in our ratings this week in the top 8 teams, apart from Adelaide extending their lead at the top of the ratings system. We are perhaps seeing a little bit of order appear in our top 8 after the logjam that existed a few rounds ago as well.


Last week our three biggest games on our match importance rating were Adelaide v North, St Kilda v Geelong and Hawthorn v GC. Given the relative strength of the teams in those last 2 games, I was a little disappointed that my new metric saw them as important, but after a big upset win by St Kilda, I can see why. With that loss, Geelong has dropped from 2nd to 5th on our simulated season ladder, with their top 4, top 2 and top 1 chances falling by between 12% and 18%. North also felt the impact of that loss, falling in all of our ladder position measures.


Our simulated season table below shows that the biggest impact on the weekend was probably felt by


We now see our top 2 rated teams also heading the top of our simulated season, with Hawthorn and Adelaide opening up pretty big gaps on the rest of the field in the top 4, top 2 and top 1 races.

Port Adelaides remain a roughly 1 in 5 chance to jump into the 8 after their bye, with St Kilda now making a big leap as a potential candidate to join them. They jump into finals roughly 17% of simulations, up from 9% last week.



Fremantle also becomes the 3rd team to not feature in finals in any of our 10000 simulated seasons after their big loss to a relatively poorly rated Collingwood.

Round 13 Results

The first bye round of the year saw my ELO model managed to tiptoe through the horror round 12 correctly tip 4 of the 6 games with an MAE of 25.5. Like last week – the model struggled to separate the teams in both matches that it got wrong (Bulldogs v Geelong and Freo v Port Adelaide).

The main mover in our ELO ratings were Geelong, after their dominating win over the Bulldogs, lifting them by 28 rating points and jumping into a clear 3rd spot on the ELO ladder. Adelaide holds their spot on top during the bye, while interestingly Fremantle has almost got themselves back to the 1500 point mark that is our league average.


I introduced the match importance rating last week to try and quantify the relative effect a win or loss in a match could have on the end of season finishing position of a team. Last week, the Bulldogs v Geelong game was the most important and we can see the effect this has had on the Bulldogs in our simulated season – they have dropped to 7th on our simulated ladder, with their Top 4 and Top 2 probabilities dropping by 19% and 16%, respectively.


Geelong and Hawthorn are firming as our favourites for the top 2, both having almost a 50% of finishing top 2 and roughly a 25% chance of finishing as minor premiers. We are perhaps finally starting to see a big of order amongst our teams as we get further into the season.

Port Adelaides loss also saw their Top 8 probability drop from 36% to 22% clinging as the only team currently outside of the top 8 with a greater than 10% chance of jumping into it.



Round 12 Results

My ELO model managed to tiptoe through the horror round 12 with a respectable 7 out of 9 tips and an MAE of 31.2. The two games it incorrectly tipped (Port v Bulldogs and WCE v Adelaide) were both within the margin of HGA in terms of tightness, so not unexpected results. The season total percentage is now creeping up with 80 correct tips (74.1%) and an MAE of 30.6.


There were some big movers in the ELO ratings this week. Adelaide extended its lead out in front, with an impressive win against West Coast in Perth while GWS cemented itself in the top 3 of our ratings with a big win over the previously 3rd best rated team in Sydney. Hawthorn received a big bump for its blowout win against the Bombers, although I suspect that Essendon this season might cause some headaches with our rating system as we go on. The other big movers were Fremantle and Melbourne, with bigger than expected wins, albeit against very low rated sides.

I may explore the horrible rating of the Lions and Bombers but the relative ratings difference between the Bombers and the 3rd worst team in the league (Gold Coast Suns) is 65 rating points (worth approximately 15 points in a game) is the same as the difference between Adelaide in 1st spot and North Melbourne in 8th spot! Pretty remarkable.


With Sydney losing big this week, they’ve dropped from 1st to 6th on our simulated ladder! North have also dropped from 2nd to 7th after a poor performance. Our model is beginning to become more certain on the top 8 as we go along, with Port Adelaide’s loss dropping their chance of a top 8 spot from 45% to 36%. The fact that the wins percentages are so close however suggests that, as per our ratings, there is little separating the top 9 teams this year.


Round 11 Results

After a few weeks struggling to juggle and balance various commitments, I think I’ve finally got into enough of a routine and automated enough of my R scripts that I can release my ELO ratings update early in the week and put my predictions out later in the week! I’ll also hope to write a bit more interesting post mid-week such as my one on the Tackle Machine, or the Round 7 rule. Here’s hoping anyway!

Anyway, after 4 weeks in a row tipping 6 out of 9 winners, my ELO model has had its first official perfect round, correctly tipping 9 winners over the weekend! It helped that the favourite got up in 8 of the 9 rounds, making it a relatively easy week to tip, but like a proud parent, that doesn’t bother me in the slightest! The MAE for this week was 29 points, bring the season total to 73 correct tips (73.7%) with an MAE of 30.53.

The updated ELO ratings are below and, for the first time since Hawthorn lost the 2014 Grand Final, they are no longer the top team in our ratings! With Adelaide’s trashing of the Saints, and Hawthorn not putting Melbourne away by as much as expected, the Crows leapfrogged the Hawks into top spot! Port Adaide and North Melbourne also impressed our model, bridging the gap to the other top teams, with a relatively close group of 9 teams now clear of the rest of the pack.


Our simulated ladder still favours Sydney, obviously taking into account their rating of 3rd, their current record and remaining draw, with North Melbourne also jumping up into 2nd spot by average. The model still has trouble splitting the make up of the top 8, but is getting pretty certain that no-one apart from Port Adelaide can jump up into the 8. For Port, their win on the weekend gave them a nice bump in ratings and lifted their percentage of top 8 finishes to 45% in our rating system.


We are also starting to see some different shapes emerge in our distribution plots for seasons, essentially signalling that the model is more certain about where some teams will finish than others. Hawthorn and North, for example, despite winning on the same amount of wins, show different distribution shapes. It will be interesting to see how this changes during the season.